1. Field of the Invention
This invention relates to a method and apparatus for mounting a piece of thin slice-base on a semiconductor wafer, which was processed in advance of being sliced from a crude material, such as silicon ingot or the like, and further processed to form impurity diffusion layers on both sides in advance, of slicing, and more particularly, for mounting the slice-base chip on the peripheral edge of the semiconductor wafer for protecting the lower end of the semiconductor wafer from any chipping off during the re-slicing process from a sheet of the semiconductor wafer into two sheets for the purpose of manufacturing a substrate for a discrete component, which is used for a transister, diode, discrete component or the like.
2. Description of the Prior Art
The applicant of the present invention previously suggested, in his Japanese patent provisional application No. Hei 1-293613, and also from other prior art, such as the Japanese patent provisional application No. Sho 64-19729 or U.S. Pat. No. 4,261,781, that the idea of manufacturing substrates for discrete components by re-slicing a sheet of a semiconductor wafer, which is formed with an impurity diffusion layer on both sides in advance, into two sheets from substantially the center portion of core thickness of the sheet in order to obtain two sheets of wafers, having an impurity diffusion layer on one side and a plane surface on the other side; however, there is no suggestion to mount any thin slice bases on the periphery of the semiconductor wafer upon the completion of re-slicing process in the above prior art.
In addition, the applicant of the present invention also suggested, in his Japanese patent application No. Hei 1-137037, a technology for re-slicing a semiconductor wafer having impurity diffusion layers on both sides of the wafer processed in advance before the re-slicing process in order to improve the productivity of producing the semiconductor wafer.
In the aforementioned suggestions by the applicant, as a suggested means of mounting the slice base on the peripheral edge of the wafer, for example, the slice base is mounted with one wafer by using an adhesive on the peripheral edge of the wafer, which is aligned in advance on a wafer magazine.
This conventional means, however, has the following disadvantages as shown in FIG. 1: a slice base(P) tends to incline in advance from a wafer(W) until an adhesive(C) has been solidified, wherein a shortage of adhesive strength and errors in the accuracy of measurements between them are caused, or as shown in FIG. 2, an adhesive falls in drops downwardly along a wafer surface wherein it causes an irregularity on the surface of the wafer to spoil the workabilities of subsequent processes.